Safety manipulating device for machinery.



W. W. DEAN.

SAFETY MANIPULATING DEVICE FOR MACHINERY.

APPLICATION FILED MAR. 15, I913.

Patented Feb. 8,1916.

V i Q onnron.

WELIAIII W. DEAN, 01E GHIGAGQ, ILLINOIS, ASSIGNOR, BY MESNEASSIGNIQIENTS, T

BENJAMIN ELECTRIC MANUFACTURING- ronarron orrntrnors.

COMPANY, 015 CHICAGO, ILLINOIS, A COB- SAFETY MANIPULATING DEVICE FORMACHINERY.

intents.

Speeificationof Eetters Patent.

Patented lFeh. g, 191d.

Application filed March i5, 191%. Serial No. tattle. 1

provements in Safety Manipulating Devices for Machinery, .of whichthefollowing is a full,'clear, concise, and exact descrlptron, referencebeing had to the accompanying drawing, forming a part of thisspecification.

My invention has for its object the provision of a simple and efleotlvetripp ng mechanism for punch presses and the like whereby completesafety to the operator is assured and the labor ordinarily involved iseliminated. In. most machines of this type. a considerable efiort orpull is required to trip the clutch,- and whether this is accomplishedby hand levers or foot levers-"or a combination of both, it becomes atiresomematter to the operator of the machine in the course of a dayswork. These machines are often operated many hundreds of tlmes per day,and even though the treadles or levers be arranged to makethe work aslight and convenient as possible, the labor involved 1n a day isconsiderable. In addition, the operators attention is divided betweenthe work being done by the press and h1s own efforts in operating theclutch. As a consequence the operators efiiciency is greatly 1mpaired,he becomes tired and careless, inattentive to the work, with unprotectedma chines accidents are liable to occur, and 1n general the result isunsatisfactory to both employer and employee. By my invention,

I however, the operator is relieved of all tiresome labor, his safetyisassured, only the natural movementsof thearms and hands in removingthe latterfrom the danger zone are required to cause the o eration ofthe press, and his speed and e money are thus materially enhanced. t

The accompanying drawing illustrates one embodiment of my invention, inwhich:

Figure 1 is an elevational view in perspective of a .punch press embodyng my 1nvention. Fig. 2 is a diagrammatic view of the 'electric'circuitand apparatus involved, and Fig. 3 is a similar View showing a furtherrefinement in the electrical apparatus.

Referring to Fig.1 the clutch trip rod 10 is pivoted at its Wer end to alever 11,

which is fulcrumed to the side of the frame of the machine as at 12. Asuitable spring 13 serves to normally raise the lever, trip, rod andother parts attached thereto.

In order to trip the clutch, a suitable solenoid 14: is attached to theside of the machine, the core of which is connected by link 15 to thelever 11 as indicated. When the solenoid is energized it serves to drawin its core and pull down the lever 11 and trip rod 10, thus trippingthe clutch and permitting the punch or similar part to be operated bythe power driving the press. The solenoid thus does the actual work oftripping the clutch and the operator is not called upon to expend anylabor to perform that operation. In order that this solenoid may beconveniently operated by the operator of-the press and at the same timeguard against any injury to the hands by having them caught by thedescending punch, the said solenoid is controlled by two switches, 15,16 one on either side of the table, bed or platform of the press, whichmust be operated simultaneously to cause the operation of the solenoid.These switches may be placed on the upper face of the bed, on the sideas shown or elsewhere at some distance from the punch and so as to beconveniently reached, one by, each hand of the operator, as he stands orsits at the machine.

After placing the work in position, the operator withdraws his handsnaturally from the danger zone and rests them conveniently upon the twoswitches, which may be made to operate by a slight pressure of thefingers or by the weight of the hand, and the clutch is immediatelytripped and the punch operated. The operation is then repeated asquickly as desired. The operators attention is thus mainly devoted tothe work in hand and not upon the tripping of the clutch. He is assuredof perfect safety since the clutch cannot be operated until both handsare withdrawn. And he is not fatigued by the incessant foot or handlever work. The work is more quickly done, since the solenoid respondspractically instantaneously, and it is not necessary to attentivelyfollow any particular sequence of hand and foot operations as in thecase of some safety moving lever or part, thus necessarily retarding thetripping operation both mentally and mechanically.

Fig. 2 illustrates a simple and effective arrangement of the circuits;in which the two switches, 16, 16 are in series with the solenoid 14. ofthe circuit, as indicated, lead to any suitable sourceof current, whichmay be the light and power circuit of the building where the machine isbeing used, a convenient manner of connecting therewith'being throughthe medium of an ordinary attachment plug and lamp socket. The source ofcurrent may be either alternating or direct, assuming the solenoid to beof suitable construction to operate on either.

Fig. 3 illustrates a, method of economizing current and magnetmaterials, by providing the solenoid with a low resistance winding andhigh resistance winding, the latter being short circuited during thepulling stroke of the solenoid core. This is accomplished, as shown,through the medium of contacts 17 and connecting conductors and V theleverll. When the solenoid has completedor substantially completed itspulling stroke, the-lever 11 strikes against the projection on the lowercontact 17, thus separating such contacts and throwing the highresistance coil into the solenoid circuit. It

is permissible to so reduce the holding current because less mechanicalwork is required ofthe solenoid at this time than at the beginning ofthe stroke. Besides, the solenoid is' magnetically stronger and exerts agreater pull with the core drawn home or nearly so than at the start,particularly if an iron clad solenoid be employed as would likely be thecase since the magnetic circuit is then completed or substantially so.Also.

a quicker re ease is secured since the current and therefore themagnetization is reduced to that just suflicient to hold the core andthere is less liability of the core sticking in its holding position byreason of the residual magnetism. 'Moreover, a smaller and cheapersolenoid with less copper can be employed without overheating since for.the

rief interval required for the pulling stroke the coil may be subjectedtov a heavier The conductors current than it would safely Qca rrycontinuously. This arrangement therefore results not only in an economyof current and materials but in a quicker and more.

positive acting device. The presence of the I high resistance in thecircuit at the time of opening the switches 16 also prevents or greatlyreduces sparking at the contacts of said switches.

While I have in the foregoing described a specific embodiment orembodiments of my invention it will be understood that this inventionmay take various forms both in detail and in general form, withoutdeparting .device being arranged to be energized only when said switchesare operated simultaneously, whereby the actuation of said clutch tripis solely effected upon the operation of said. switches, and means,operated automatically when said clutch is actuated, for

reducing the current flowing through-said 7 device, for the purposes setforth.

2. The combination with a press ha'ving a clutch trip, of safetyactuating means for said trip, said actuating means comprising asolenoid for directly actuating said trip, said solenoid having a highresistance winding anda low resistance winding, a pair ofseparatedswitches connected inseries with said solenoid and with eachother, and

switching mechanism adapted to be operated when said clutch trip isactuated, to connect said high resistance winding in circuit, for

the purposes set forth.

- In witness whereof, I have hereunto sub- Y scribed my name n thepresence of two witnesses.

LIAM W. DEAN Witnesses:

G. E. KANE,

ANNE SOLOMON.

